1. The Field of the Invention
The present invention is related to a passenger airbag module. More particularly, the present invention is related to a novel passenger airbag module with a disc-shaped inflator and novel cylindrical housing, suitable for use on the passenger side of a vehicle.
2. Technical Background
Inflatable vehicle occupant safety restraint systems, or “airbag restraints,” are mandatory on most new vehicles. Airbag restraints commonly contain a collision sensor, an inflator, and an airbag cushion. The airbag cushion is typically housed in an uninflated and folded condition in the steering wheel on the driver's side of a vehicle and in the dashboard on the passenger side of a vehicle. For ease of manufacture, assembly, and installation, many airbag restraint systems come pre-packaged in module form.
In the event of an accident, the collision sensor measures abnormal deceleration and triggers the inflator by means of an electronic signal. Upon receipt of the signal from the collision sensor, the inflator rapidly produces a quantity of inflation fluid which inflates the cushion and protects the passenger from harmful impact with the interior of the car.
Airbag modules were first used on the driver's side of a vehicle to protect the driver from impact with the steering wheel or steering wheel column area. When driver's side airbag modules were applied to the passenger's side of the vehicle however, these known air bag modules suffered many disadvantages.
The existence of a steering wheel and column on the driver's side of a vehicle minimized the space that an inflated airbag needed to fill in order to protect the driver. The space between a passenger and the front panel of a vehicle interior on the passenger side, however, is significantly larger, and a larger airbag is needed. To overcome the problem of inflating larger airbags, larger inflators were used to produce the greater amounts of inflation fluid needed to fill an airbag that would occupy the larger space. The problem with these inflators, however, is that on the passenger side of the vehicle the dashboard or instrument panel provides less space to insert the airbag module and less structure to which the inflator can be attached. Airbag modules with larger elongated inflators do not fit efficiently into the instrument panel on the passenger side of the vehicle.
Another problem with the elongated nature of known inflators is that these inflators extend well beyond the point of attachment of the inflator to the instrument panel. This additional weight on the back side of the instrument panel causes additional torque or pivot forces on the instrument panel which is usually made of plastic. The instrument panel can twist or become detached from the inflator which can negatively effect the trajectory of airbag deployment or create cracks or deformations in the instrument panel.
Most known airbag modules made for front deployment are somewhat bulky and heavy. This may not pose a problem when installing these airbag modules in the steering wheel column because the existing structure of the steering wheel column could support the heavier and bulkier inflators. This support structure, however, is not found on the passenger side of the vehicle. Accordingly, most known airbag modules require additional, and often complex bracketing to support the module within the instrument panel on the passenger side of the vehicle. This additional bracketing results in increased cost in materials and assembly. Further, the additional bracketry takes up space.
Other known passenger side airbag modules include housing members that are susceptible to deformation during inflation. This problem is exacerbated on the passenger side of the vehicle because of the increased combustion forces needed to fill the larger space. This can also negatively affect the trajectory of the airbag's inflation which may cause it to deploy out of position or inefficiently. Yet another problem with known passenger side housings is that they are square or rectangular with the corresponding airbag cushion having corners at transition points that are more susceptible to stress and consequent damage.
Another problem with many known inflators is that the source of inflation fluid is pressurized gas, which requires the inflator to serve as a pressure vessel. This in turn requires these known inflators to use the thicker material needed to safely contain the pressurized inflation fluid. Thicker material increases costs and weight which decreases installation efficiencies.
Accordingly, a need exists for an airbag module with a simplified, smaller, and lighter weight design that can also fully inflate an airbag cushion on the passenger side of the vehicle. A further need exists for an airbag module with a smaller or shallower profile that can efficiently fit into the instrument or front panel of the passenger side of the vehicle. Further a need exists for such an airbag module that does not extend well beyond its point of attachment into the instrument or front panel of the vehicle. Still further, a need exists for such an airbag module that does not need to serve as a pressure vessel, yet that can produce enough inflation fluid volume to sufficiently inflate an airbag on the passenger side of the vehicle. Additionally, a need exists for an airbag restraint module that has a lightweight, sufficiently strong housing to resist deformation upon inflation. Such a novel airbag module is disclosed and claimed herein.